1. Field of the Invention
The present invention relates to a group III nitride semiconductor optical device, an epitaxial substrate, and a method of making a group III nitride semiconductor light-emitting device.
2. Related Background Art
Nonpatent Literature 1 discloses a light-emitting diode made of a gallium nitride based semiconductor. This light-emitting diode is fabricated on a (11-22) plane of GaN. The light-emitting diode has an emission wavelength of about 420 nm, about 520 nm, or about 620 nm in the range of blue to amber.
Nonpatent Literature 2 discloses a laser diode made of a gallium nitride based semiconductor. This laser diode is fabricated on the m-plane of GaN. The laser diode has an emission wavelength of 499.8 nm.
Patent Literature 1 discloses a laser diode fabricated on a {11-22} plane of a GaN substrate. This laser diode has an emission wavelength ranging from 480 nm to 650 nm.    Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2009-71127    Nonpatent Literature 1: Japanese Journal of Applied Physics, Vol. 45, No. 26, 2006, pp. L659-L662    Nonpatent Literature 2: APPLIED PHYSICS LETTERS 94, 2009, 071105